Tremolo effect unit

Abstract

A tremelo effect unit and a stringed instrument incorporating a tremelo effect unit include a pivotal support which, in use, secures at least one string of a stringed instrument under tension. The tremelo effect unit can include a resilient biassing element, typically in the form of a compression spring, which pivotally urges the support against the tension of the string. The resilient biassing element is arranged to act in a direction substantially opposite to a direction in which the instrument string extends.

I claim: 
     
       1. A tremolo effect unit for a stringed instrument, said stringed instrument having a body, a head, a bridge fixed to a first surface of the body and at least one instrument string coupled to said head and passing over said bridge, said tremolo effect unit comprising a pivotable support for securing at least one instrument string under tension between said pivotable support and said head, said pivotable support being pivotably moveable relative to said bridge,   lever means coupled to said pivotable support for effecting pivotable movement of said support by a performer, and   resilient biasing means disposed between said pivotable support and said body to pivotably urge said support against the tension of said at least one string, said resilient biasing means extending from said support to a mounting point on said body, said mounting point being located such that said support lies between said mounting point and said head,   said body being shaped to define a cavity, said cavity having a mouth opening onto said first surface, said support being in non-coupled pivotable engagement with said mouth, and said support extending through said mouth into said cavity.   
     
     
       2. A tremolo effect unit as claimed in claim 1 wherein said body is structured to configure said cavity with a taper adjacent to said mouth to facilitate pivotable movement of said support about said mouth. 
     
     
       3. A tremolo effect unit as claimed in claim 1 wherein said support includes a spacing portion located within said cavity, said spacing portion being tapered to facilitate pivotable movement of said support about said mouth. 
     
     
       4. A tremolo effect unit as claimed in claim 3 wherein said support includes a lip adapted for seating on said mouth, said lip having an at least partially rounded surface for pivotable engagement with said mouth. 
     
     
       5. A tremolo effect unit as claimed in claim 1 wherein said resilient biasing means comprises at least one compression spring disposed between said pivotable support and said body. 
     
     
       6. A tremolo effect unit as claimed in claim 3 wherein said support comprises a plate fixed to, and substantially perpendicularly disposed with respect to, said spacing portion of said support, said plate being dimensioned to engage against said cavity when said support is pivoted in use, thereby limiting the extent to which said support is pivotable with respect to said body. 
     
     
       7. A tremolo effect unit as claimed in claim 4 wherein said cavity has a hole opening onto said first surface, and   said support comprises a sleeve having a lip mounted thereon, said sleeve penetrating into said cavity through said hole and said lip being seated in said mouth.   
     
     
       8. A stringed instrument having a body, a head, a bridge fixed to a surface of said body, and an instrument string having a first end coupled to said head and passing over said bridge, said body defining a cavity wall forming a cavity disposed such that said bridge lies between said cavity and said head, said cavity having a mouth narrower than said cavity and open to said surface, said mouth thereby defining an interior and an exterior of said cavity, said stringed instrument further including a tremolo effect unit comprising a support for securing a second end of said string above said surface such that said string passes under tension from said support, across said bridge, and to said head, said support having a portion extending through said mouth and into said cavity, said support moveably seated in said mouth to permit said support to rock back and forth in said mouth,   compression spring means disposed in said interior of said cavity between said portion and said cavity wall, said compression spring means extending from said portion in a direction away from said head and disposed to exert a bias in opposition to said tension of said string to maintain said support in an equilibrium position in which said tension in said string equals said bias of said compression spring means, and   lever means coupled to the support exterior to said cavity for effecting rocking movement of said support about said equilibrium position.   
     
     
       9. A stringed instrument as recited in claim 8 wherein said support includes a lip adapted for seating on the mouth, the lip having an at least partially rounded surface for rocking engagement with the mouth.